Handbook of green building design and construction pdf

What integrative factors influence the performance of a healthy and sustainable building? This, while it may be important for clients and architects to know, is frequently not very transparent.

LEED v4 Practices, Certification, and Accreditation Handbook, Second Edition, provides users with a practical user-friendly roadmap that presents the guidelines for selecting the LEED v4 rating system to better fit a particular project e.

Illustrates the Global Relevance of SustainabilityApplicable to roads, bridges, and other elements of the infrastructure, Green Building with Concrete: Sustainable Design and Construction, Second Edition provides an overview of all available information on the role of concrete in green building.

A handbook offering viewpoints from worldwide experts. The objective of Sustainable Communities Design Handbook is to ensure a better quality of life for everyone, both now and for generations to come. This means creating a better and safer environment internationally through the sustainable use of natural resources, encouraging sustainable development which supports a strong economy, and ensuring.

Green Construction is a specialized and skilled profession, and the author has extensive experience in this field. With this in mind, the reference is designed to provide practical guidelines and essential insights in preparing competent and professional looking?

Project Analysis Reports? Project Status Reports?. Regional Materials 6. Rapidly Renewable Materials 6. Green Office Equipment 6. Forestry Certification and Certified Wood 6. Third-Party Certification Chapter Seven. Indoor Environmental Quality 7. General Overview 7. Factors that Affect IEQ 7. Ventilation and Filtration 7.

Building Materials and Finishes—Emittance Levels 7. Water Efficiency and Sanitary Waste 8. Overview 8. Water Fixtures and Reducing Water Strategy 8. Impact of Energy and Atmosphere 9. General Introduction 9. The Building Envelope 9. Intelligent Energy Management Systems 9. Electrical Power and Lighting Systems 9. Solar Energy Systems 9. Federal Tax Credits for Energy Efficiency 9.

Fire Suppression Systems Chapter Ten. Green Design and Building Economics General Costs and Benefits of Green Design Life-Cycle Costing Tax Benefits and Incentives Other Green Building Costs Green Project Commissioning General Overview Fundamental Commissioning Basics Building Commissioning Objectives—Costs and Benefits Planning the Commissioning Process Commissioning Authority Commissioning Service Provider The Commissioning Process Chapter Twelve.

Project Cost Analysis Often the Green choice can actually reduce initial costs, but even where they are increased, savings can be made over the life time of the building.

Many Green specification choices are more expensive than conventional alternatives at present, because the market is so small for Green products, but as consumer demand changes prices will come down. Often Green products are inherently cheaper as they used recycled or by-product materials, however they are nor always widely available and the industry is still trying to off-load toxic and environmentally damaging materials.

Weighing up choices about specification involves assessing the payback in terms of savings of energy and reducing environmental damage. We all have a responsibility to make these calculations, but we also need to consider how long materials will last and what will happen to them when they are taken down or thrown away.

Life cycle costing is a well established concept, though rarely applied when short term considerations are so universally prevalent. However if the environmental impact and embodied energy costs are brought into the analysis, the picture changes radically. As taxes and other government controls make the producer and consumer pay the real environmental costs, attitudes are still slow to change.

The introduction of the landfill tax has created many new environmental initiatives but has not yet significantly altered waste practices. However a new recycling industry is slowly developing. The environmental costs of dumping waste are very high, and as these become more immediate the construction industry is already changing its practices.

Building sites no longer need to be covered in rubbish and waste materials can be sorted tidily and re-used. Concrete and steel from demolished buildings is now carefully extracted and recycled and the technology to make this possible is readily available and cost effective. Specification decisions need to take into account what will happen when the building needs maintenance, or elements have to be replaced. Can the materials be recycled, will this reduce long term costs, and so on?

Costing of embodied energy can highlight the advantages of re-use, rehabilitation and conversion of existing buildings, normally considered to be more expensive than demolition and new build. Whether to build new or convert an old building or whether the activities need a building at all. Where should it be sited, in an existing settlement or out in the country generating the need for more traffic, or could public transport provision influence decisions?

At present only larger projects tend to require an environmental impact statement, but eventually, all building proposals should, perhaps, be required to assess their environmental impact, beyond the present, relatively low energy saving requirements in the building regulations.

This would ensure that green issues would be taken into account in all projects. Unfortunately it is often assumed that a building can be designed and then someone can come along to make it energy efficient or green at a later stage. This is a mistaken approach as initial strategic and design decisions may rule out green principles. Anyone with a building or considering development should seek advice about environmental issues right from the beginning. It is also important to understand that assembling a collection of green materials will not necessarily result in a successful building.

The importance of good design cannot be under- estimated. It is essential to establish a good partnership where all are committed to the idea of a green building and are willing to take responsibility for the decisions that follow. With a big building requiring architects, structural engineers, quantity surveyors and mechanical and electrical engineers, it is essential that the whole team are involved in the design process from the beginning and are equally committed to the green approach.

Alternatives such as natural ventilation need to be considered from the beginning. Even with a small building, such as a house, environmental issues must be considered from the beginning of the process. It is not unusual to be contacted by clients who have appointed an architect to design an environmentally friendly building, who then ask for green experts to come along and give the consultant a crash course in how to turn their design into something that might be a little less damaging.

Green building is not a separate specialist discipline, it must be fully integrated with the whole process. Clients need to appoint consultants who fully understand how to undertake the green building task and have some experience of working in this way. They should also visit examples of good practice and this may well involve some travelling.

In most cases not every problem has been solved or even attempted, so you may have to visit several projects to see everything you are interested in. Finding architects and other consultants who understand green principles is getting easier and clients are best advised to contact one or more of the organisations listed in this book for lists of professionals in their area rather than using the establishment professional bodies. Finding builders who are familiar with green building methods is also not too easy.

Even where lip service is paid to environmental principles, the construction industry is notoriously conservative and workers on site will need constant supervision and even re-training. High levels of insulation can be pointless if careless building leaves cold bridges and gaps. These will not be apparent once everything is covered up. You may not want to source material from far afield as transport costs will put up the embodied energy costs and many of the best ecological products come from Scandinavia and Germany.

Often more conventional builders merchants will not welcome enquiries about the source of materials such as timber and will not be able to advise you on the nature of toxic emissions from different products. Others can appear to be environmentally aware and will tell you that their timber or products are from sustainable or renewable sources. However a simple question as to what accreditation or authentication system has been used will frequently produce a blank stare!

Anyone setting out with the intention of creating a green building will be helping to blaze a trail and the greater demand for environmentally friendly materials and products, the easier they will be to obtain. Market pressures as well as changing public sector policies about specification will make green building easier. There are signs that the industry is rapidly becoming aware of the demand for environmentally friendly products and while only one paint product, so far has a Eco-Label, many more are likely to follow.

Each will illustrate a range of attempts to achieve green results. In most cases, good designers will make it clear that they have not been able to achieve everything that they intended and that the building may not be as green as they like. This is not surprising when green building is such a new idea. Each new project allows the boat to be pushed out a little further and experimental techniques to be tried and tested.

Gradually the accumulation of knowledge and experience will make it easier to improve good practice in the future. We have selected a handful of buildings which show a range of green building ideas in practice. Only a brief account is given of each project, though future editions of the Digest may include more detailed case studies and working drawings.

There are many other examples of green buildings, not illustrated here both in the UK and further afield and the potential green builder will need to learn from a wide range of examples to see all possible approaches and techniques tried out.

The scheme is intended to put into practice a wide range of green principles and is one of the best examples of an holistic approach to be found in the UK. The self builders are now in residence and will not necessarily welcome constant visits from curious onlookers so they are going to run occasional courses to demonstrate the various features of the houses.

Timber was treated with borax to avoid normal toxic chemicals. All other toxic materials have been eliminated as far as possible. A considerable amount of second hand materials have been used as well as locally sourced green timber. High levels of recycled paper insulation have been used mm in the walls and mm in the roof and there are some passive solar gains. The street front roof uses pan tiles and was designed to appease the planning authority but at the back a planted roof and timber cladding present a greener solution.

All rainwater will be collected off the roofs with the aid of timber gutters and then purified and used in the building again using system designed for this scheme making them almost entirely independent of mains water. The scheme has a mortgage from the Ecology Building Society. This extension to the Horniman Museum was built to provide educational facilities and displays on local and global environmental issues It was decided that the building itself should be a model of green thinking, displaying energy efficient technology and using environmentally friendly materials and construction techniques.

The building, therefore, is a green exhibit in itself. Constructed largely of timber, obtained from sustainable sources, the structure includes highly innovative triangular timber beams which support the floor and roofs and also serve as ventilation ducts.

Recycled newsprint insulation and breathing wall constriction have been used. There is a green roof and water is recycled through a system of ponds which are part of the habitat around the building. All paints and other treatments were using non toxic, organic paints. Salt 3. There are three main frames which were put up over a weekend with the posts built off concrete pads to try and cope with the West coast of Ireland driving rain.

One of the advantages of the Segal post and beam frame system is that major alterations can easily be made and in this case the area of window on the south facade was changed without any additional cost after the main walls were up! Recycled newsprint insulation has been used in the walls and roof. Much of the timber was sourced from forests which claimed to employ sustainable planting strategies, in Ireland and treated with Borax.

Even the cedar cladding came from Ireland. Roofing slates were Irish grey green slates recovered from a building which was being demolished in Sligo town. Internal walls are finished with lime. Salt Plate 8. Photo: Architype Ltd recovery ventilation system has been installed and annual heating costs are proving to be extremely low.

Photo: Architype Ltd Plate Rothwell 3. Because of the environmental requirements to achieve high levels of insulation, the house is constructed from a timber frame, inside the stone shell. House in County Laois, Republic of Ireland. Photo: W. Rothwell and the old. Any materials such as the slates were carefully recycled. This made it possible to use breathing wall and roof technology with recycled paper insulation. Timber was obtained from Irish sustainable sources.

Water based paints and stains were used throughout. The final result has a timeless quality with even the modern extension and conservatory sitting in harmony with the existing building. Ireland This is an example of where an existing redundant structure, in this case a disused and derelict mill and a barn, have been converted to provide a house.

There are many such redundant agricultural and industrial buildings in towns and the countryside and it is a waste of energy and materials for these to be demolished and cleared to landfill sites unless the buildings are in dangerous condition..

Often there are planning restrictions on the use of such buildings which can mean that they are allowed to sit empty and decay, thus robbing the environment of reminders of the past. There can be some opposition to conversion from environmentalists who are trying to protect wildlife habitats for bats or Barn Owls, others would like to see buildings such as mills preserved as working mills rather than converted into houses. Such factors should be carefully thought through before conversion is pursued.

Sadly many such buildings are now demolished to feed the fashionable demand for second hand materials so these contradictory issues have to weighed carefully. The Crossgar project is an experiment in how to re-use such structures and involves several phases. There are environmental problems in retaining existing structures as it may be hard to achieve the high levels of insulation expected in green buildings, but even where this is not achieved, overall embodied energy savings may justify such projects.

In the Crossgar example, a high level of second hand materials have been used including polystyrene insulation rescued from a cold store which was being demolished. Second hand and locally sourced timber has been used. Heating is from a gas boiler and some passive solar benefit is derived from a conservatory.

A passive ventilation system, rainwater recycling and grey water reed bed treatment are part of Phase 2. A key policy on this project was to avoid wastage and every scrap of wood and stone has been reused on site in some way.

Not a single skip was used to take waste material off site. The College decided to make the building a showcase of green ideas and has been successful in that the building won the Green Building of the Year Award While the somewhat reproduction style of architecture meant that the building has used brick and a substantial amount of concrete in the basement, the college took the remarkable step of buying an area of Tasmanian Eucalyptus Forest to offset any criticism of CO2 emissions which they had not been able to prevent.

Other tree planting to replace trees that had to be cut down, was carried out in Oxford and the design incorporates nesting boxes and other nature conservation features. The embodied energy costs of the building were carefully worked out and this influenced the choice and specification of materials. Recycled newsprint insulation was used with mineral fibre in the basement. Timber windows were selected and plastics materials excluded. Demolition materials were used for hard-core.

Low formaldehyde materials and non toxic paints were also selected. Linacre College, Oxford Photo: W. Rothwell A highly energy efficient heating and heat recovery system was used with passive stack ventilation. There have been problems with a waste water recycling system but these are being remedied. Careful auditing and calculations and monitoring mean that the success of this building in environmental terms can be evaluated if the results are published. The larger the circle the worse an environmental impact is thought to be in the opinion of the author.

Marks on each Table will only indicate poor records relative to other products on the same Table. Less well accepted are the more detailed headings under which life cycle analysis is performed. Those we have used are based on those used by other LCA professionals, but developed specifically for this particular use—presenting information about building products in a simple table format. This would entail trying to judge the relative importance of, for example, 50g emission ozone depleting CFC with a hard-to- quantify destruction of wildlife habitat.

A blank represents a zero score, meaning we have found no evidence of significant impact in this category. Where a score is assigned, bear in mind that the scores are judged relative to the other products on the same Table. The following symbols represent the impact scale Production This group heading covers the extraction, processing, production and distribution of a product.

This energy is almost always in the form of non- renewable fossil fuels. Resource Depletion biological Biological resources, whether of timber in tropical forests or of productive land at home, can all be destroyed by industrial activity.

These can only be counted as renewable resources if they are actually being renewed at the same rate as their depletion. These include all minerals dug from the ground or the sea bed.

Global Warming Global warming by the greenhouse effect is caused chiefly by the emission of carbon dioxide, CFCs, nitrous oxides and methane.

Ozone Depletion The use of CFCs and other ozone-depleting gases in industrial processes still continues despite many practicable alternatives.

Toxics Toxic emissions, to land, water or air, can have serious environmental effects, none of which can ever be completely traced or understood. Acid Rain A serious environmental problem, causing damage to ecosystems and to the built environment.

Caused mainly by emissions of the oxides of sulphur and nitrogen. Photochemical Oxidants The cause of modern-day smog, and low-level ozone, causing damage to vegetation, material and human health. Hydrocarbon and nitrogen oxide emissions are chiefly responsible.

See the specific Product Analysis section for an explanation of each case under this heading. Use This group heading covers the application at the site, the subsequent in-situ life and the final disposal of a product. The potential impact, and therefore potential savings, are enormous. Health Hazards Certain products cause concerns about their health effects either during building, in use or after.

Other Again no list like this can ever be complete. See the specific Product Analysis section for an explanation of each case. Alert Anything that we feel deserves special emphasis, or that we have come across in the literature that is not dealt with elsewhere, is listed here on the Table.

Both conventional fossil-fuel energy and alternative renewable sources are considered, together with the practicalities of alternative renewable sources. Different types of equipment e. Its primary cause, though there are others, is the CO2 emissions from the burning of the fossil fuels—coal, oil and gas. These fossil fuels are themselves in limited supply. Optimistic estimates for world crude oil production expect that it will peak within the next five years, and from thereafter be in decline.

Action to reduce the use of fossil fuels must begin now. Why Me? As a building designer, specifier or in any other capacity responsible for the choice of heating systems in a building, you have more opportunity to do something about global warming than anyone except the politicians and energy multinationals.

It must be emphasised that the science behind these figures is still subject to much debate, but in view of the probable threat, it would be prudent to adopt the precautionary principle and act to substantially reduce CO2 emissions. The governments of the most progressive countries on this issue e.

These figures also assume reductions of other greenhouse gases, and an end to deforestation. Even if all new buildings were designed and built for zero CO2 emissions, this would not, on its own, be enough to meet this target. The Truth About Being Economical The supply of energy can either be capital intensive, as in the case of wind power, where a high initial investment is needed, but the running costs are minimal, or expenditure intensive, as is the case for most fossil fuels where the running costs fuel dominate.

It would seem to be common sense that for any long-term project such as heating a building capital intensive, low-running-cost options should always work out cheaper in the long run, and therefore be generally the most widely used. That this is not the case is due, in part, to the short termism of the suppliers of capital. It is also due to the effects of judging these costs against the benchmark of the marginal cost of using the equivalent amount of the cheapest fuel, usually gas or oil, and the fact that the true costs of these options are seriously underrated if their full environmental costs were also to be included.

They want the services it can provide: comfort and warmth; hot water for washing; light to see by. From to average temperatures in dwellings rose from Of these improvements, two thirds were achievable by increased insulation, one third by increased appliance efficiency. The effect of switching fuels was not included. Over two thirds would actually save money. Firstly energy requirements should be minimised by good design.

A key strategy for sustainable development is the appropriate use of resources and technology. Also, as a developed country, the convention commits us to returning emissions of each greenhouse gas to levels by European Environment and Energy ministers also agreed that the community as a whole should stabilise CO2 emissions by at levels.

The UN commitment is the strongest, and is aimed at sustainability. Even if industrialised nations stabilise at levels, global warming could still rise at twice the rate considered tolerable by sensitive ecosystems and vulnerable populations.

Crucially, realistic replacements are here already for heating buildings, but not so for the other uses of fossil fuels. Passive solar design is by far the best environmental option for space heating. This strategy only deals with global warming and resource depletion issues— localised pollution effects from fossil fuel burning are a further complicating factor.

Maximise use of renewable sources wherever possible—e. If you must use a backup fossil fuel, use gas or LPG if not on mains and a condensing boiler, with good controls and meters. District or community heating systems offer potential for economies of scale that make renewables such as active solar for space heating, or even wind and biogas, worthwhile.

All that we can determine is how quickly we move towards the goal. Nevertheless, it is still a finite resource, and as the other fossil fuels run out, is likely to be used in increasing amounts, so its lifetime could be much shorter. Global Warming Burning coal releases more CO2 than other fossil fuels,6,11 and the deep mining of coal releases methane, another potent greenhouse gas, to the atmosphere.

It is this sulphur content that gives rise to SOx the chief acid rain-forming gases. Particulates from coal burning are around 3 times the quantity as from oil. Global Warming Burning of natural gas creates the least amount of CO2 per unit of heat than for any other fossil fuel, but it is still a considerable amount—around 60 kg. Likewise with emissions causing Acid Rain and Photochemical Smog, and with Particulates and Toxics emissions, oil combustion falls between coal and gas.

Piper Alpha. Other Leaks and spillages of oil, either routine or accidental, also cause concern, as does the impact of pipelines and refineries. The conversion of heat, from combustion or nuclear reactions, via steam, into electricity, is governed by the physical laws of thermodynamics, which limit the efficiency with which this can be performed. Thus the level of economically extractable reserves depends crucially on price.

Chernobyl ; long-term exposure to low levels of radiation; and security and defence issues. However, the risks of major accidents, and the geological time spans for waste-containment, have deterred the markets from investing in nuclear power in recent privatisations.

But the more wind farms are built, the less fossil fuel will be burnt and the nuclear power stations will have to be built or kept going.

Toxics Photovoltaic panels used to generate electricity directly from sunlight are manufactured in a process similar to that used in the semiconductor industry. Although the basic raw material is silicon, obtained from sand, a range of toxic chemicals is also used. So far this is not known to have caused injury to anyone. Others consider them to be objects of great beauty. Sensitive siting may be called for. Check with the manufacturer. This analyis assumes that anyone choosing a biomass fuel for ecological reasons will go to the trouble of obtaining it from a well-managed source.

Thus the combustion of biomass is CO2 and therefore greenhouse neutral, but only so long as the whole cycle of planting, growth, harvesting and replanting or regrowth with coppicing , is in place.

The actual amounts and types of pollutants vary widely, depending on the type of fuel, its state wet or dry, fresh or decomposed etc.

Biogas is essentially methane, the same as natural gas, but other impurities may be present. Well-dried wood, burnt in a modern stove that allows for a secondary combustion air-flow, can be a relatively clean option. Larger scale systems, whether burning wood chips or biogas, suited to larger institutions or district heating systems, tend to be less polluting.

Other The use of land specifically for the growing of energy crops displaces other uses such as food crops. For further information on these, the first port of call has to be the Centre for Alternative Technology at Machynlleth in Wales. Their bookshop on its own makes travelling to the Centre worthwhile, never mind the practical displays themselves, but it also does an excellent mail order service.

CAT also publishes extensive lists of suppliers of equipment for utilising renewable energy as well as consultants and other useful contacts. Indeed, care must be taken to avoid overheating in summer, and adequate ventilation and humidity reduction become the key issues.

In less than optimal settings, such as retrofitting existing buildings, or where site restrictions do not permit perfect solar orientation, backup heating may be required.

The key to efficiency in this case is to use a flexible system with fast response times, so that the solar component is allowed to contribute useful heat whenever it can. It entails little or no extra capital costs when included in the design of new building unlike active solar techniques. There are numerous books etc. The pictures here just show the very basic ideas. A growing number of examples of successful buildings exist around the country.

In order to promote passive solar building, Friends of the Earth want the Building Regulations to provide example designs with passive solar features that are deemed to conform to the regulations. This would be useful for small builders etc. FoE also want Building or Planning Regulations to include measures to prevent the overshadowing of neighbours and thereby reducing their solar performance. They estimate that at least 3 million passive solar buildings new and retrofit could be in place in the UK by The additional cost for glazing, super-insulation etc.

The energy savings of such a design will be greater than the extra payments on an ordinary mortgage. Solar systems integrated into the roof fabric can be more economical and look better too.

The technology ranges from sophisticated and expensive evacuated tube collectors to black-painted radiator panels. Solar collectors are usually able to supply all domestic hot water needs for only part of the year. Additional heating will be needed for the winter months.

The savings in pollution are not taken into account in such calculations. This is most often achieved with the use of large, well- insulated and often underground, water tanks. These are heated up by solar panels over the summer months, and then the heat is released gradually over the winter.

Heating systems based on interseasonal storage need to be designed specifically to work with relatively low temperatures of hot water—under-floor heating is well suited,29 as is warm-air circulation. With larger systems, the efficiency of the collectors, and heat loss from the store are much less crucial. It may therefore be a good strategy to include space for such a heat store in buildings designed now, even if this space is only used as a wood store for now.

Photovoltaics is a technology to watch for the future. As costs come down, and PV panels are integrated into roof tiles etc. Such systems are widely promoted in developing countries, especially China, and on a small scale, are only really suited to a rural agricultural setting. Alternatively, municipal refuse sites are a good source of biogas, but these are not strictly a renewable resource.

Between 4 and 8 large farm animals would be needed to provide enough biogas energy for the cooking energy alone of one family. The investment in plant can be paid back in under eight years compared to bought-in gas,1 and a waste disposal problem has been turned into valuable fertiliser. In cold climates, the economics of biogas suffer, as a further heat source usually a fraction of the gas produced is needed to keep the digester at an optimal temperature.

It is therefore least efficient in winter when it is needed the most. Sometimes scrap or waste timber is counted as a renewable source too. Either way, if a wood-fuelled heating system is being installed, the responsible designer will also consider the specific supply that will be used.

It is also worth bearing in mind that, like all solid fuel heating, using wood requires some input of work from the user—if not actually chopping and stacking wood, then at least in tending the stove.

This may or may not be a chore, depending on attitudes to work, but the user is more aware of the amount of energy used if it has to be manually carried rather than arriving down a pipe.

Short-rotation coppicing is currently a popular option. Many broadleaf or deciduous trees will sprout new growth when cut down to a stump, the new growth being very vigorous. Short rotation coppicing is often done on a 7-year basis, where one seventh of the total area coppiced is cut each year, or sometimes even shorter rotations of 2—3 years are used.

Coppicing is suited to a range of scales from single homes to large commercial operations supplying a district heating system. A hectare 2. Additional Benefits The growing of trees is popular with almost everyone, for its environmental and aesthetic benefits.

Coppicing may provide rural employment, and has particular wildlife benefits different to normal woodland. It may also require less management than conventional forestry as replanting is seldom needed. The solar panel provides hot water on warm sunny days; the wood stove provides both space and water heating on cold days.

Wind turbines come in all sizes from tiny ones that keep boat and caravan batteries charged to the huge ones that adorn the hill- top wind-farms of Wales. To use wind-generated electricity directly for water heating via an immersion heater e.

On a very windy site you could maybe get away with a smaller one, perhaps 1. However, for a house in a very windy spot, with no mains electricity, a wind turbine plus battery system may be the cheapest way to power a few lights, a radio and small fridge etc. There are 80, mini hydro plants in China. Whilst CHP is a much more efficient way to utilise fuels, it is still in the main designed for fossil fuels such as oil, gas or coal although it could technically be powered by biomass fuels.

The left-over heat, usually in the form of hot water or steam, is then used directly as well, for heating buildings or for other processes. The Embodied Energy of a Wind Turbine and a Stove A European study, that looked at a whole range of different wind turbines, found that most machines had generated as much power as went in to their manufacture in less than half a year. For the rest of their life expected to be around 20 years they were in energy profit,40 and therefore generated, at the least, 40 times their embodied energy.

A stove or boiler uses fuel rather than generating power, so will not make an energy profit. The following example has been calculated for a typical wood- burning stove. It demonstrates in just how short a time a stove or other heating appliance will use up the same amount of energy as went into its manufacture. About 12 days with 8 hours use a day. Converting Units: 5.

Energy Without End, M. Flood Friends of the Earth, London 8. Price, Green Print, W Karas, Friends of the Earth, London, What Are Biofuels? A Solar Heating System with interseasonal storage R. Geoff Hamilton, Dorling Kindersley, London How Renewable is Wind Energy? Though there are a wide variety of insulation materials available, they are not all suitable to every application.